Adult witness credibility: Evidence for a two-factor model

Abstract

Previous research in the areas of social, expert witness, and child witness psychology has found evidence for a multiple factor model of witness credibility. While a multiple factor model has not yet been tested with adult witnesses who are not experts, results from previous credibility research suggest that there may be at least two components of adult witness credibility: perceived cognitive accuracy and perceived honesty. The current study utilized a 3 x 3 (Perceived Cognitive Accuracy [neutral, medium, low] x Perceived Honesty [neutral, medium, low]) design to assess effects on witness credibility, verdicts, and likelihood of commission scores. Participants were 383 students from the University of Texas at El Paso. A confirmatory factor analysis showed two factors of credibility: perceived cognitive accuracy and perceived honesty. Based on these results, scales of cognitive accuracy and honesty for adult witnesses were developed. Inconsistent witnesses showed greater deficits on the cognitive accuracy scale, and witnesses with a prior criminal record showed greater deficits on the honesty scale. In addition, greater cognitive accuracy and honesty scores predicted more guilty verdicts. While further study is needed in order to generalize these findings across other trial scenarios and manipulations, the current study provides the field with a reliable and valid measure of the two central components of adult witness credibility.